Creating a Zpool

Oracle Solaris ZFS uses device names or partition names when dealing with pools and devices. For a
device, this will be something like c1t0d0 (for a SCSI device) or c1d1 (for an IDE device). For a
partition, it will be something like c1t0d0s0 (for a SCSI device) or c1d1s0 (for an IDE device). This
example creates a pool that is mirrored using two disks.

1. To create a zpool in the global zone, use the zpool create command. Typically, you use two
devices to provide redundancy.
Global# zpool create mypool mirror c2t5d0 c2t6d0

Note that the zpool create command may fail if the devices are in use or contain some types of
existing data (e.g. UFS file system). If they are in use, you will need to unmount them or otherwise
stop using them. If they contain existing data you can use the -f (force) flag to override the safety
check, but be sure that you are not destroying any data you want to retain.

2. Examine the pool properties using the zpool list command. This shows you that there is one
zpool, named mypool, with a capacity of 199 GB.
Global# zpool list
NAME SIZE USED AVAIL CAP HEALTH ALTROOT
mypool 199G 164K 199G 0% ONLINE —

Creating a Zone

To show Oracle Solaris ZFS working in an environment that is isolated from other applications on the
system, you need to create a zone. To create a zone:
1. Create a directory where the zone file system will reside, using the mkdir command. Be sure to
chose a location where the file system has at least 80 MB of available space.
Global# mkdir /zones
Note that in this example, for the sake of brevity, the root file system of the zone is a UFS file
system.
2. Configure the zone (myzone), using the zonecfg command, and specify the location of the zone's
files (/zones/myzone). Use the following series of commands.
Global# zonecfg -z myzone
myzone: No such zone configured
Use 'create' to begin configuring a new zone
zonecfg:myzone> create
zonecfg:myzone> set zonepath=/zones/myzone
zonecfg:myzone> verify
zonecfg:myzone> commit
zonecfg:myzone> exit
Again, for the purpose of streamlining, this example uses a very minimal zone. For more details on
creating zones see the Oracle Solaris Containers How To Do Stuff guide at:
https://www.sun.com/offers/details/solaris_containers.xml
3. Install the zone by using the zoneadm command.
Global# zoneadm -z myzone install
Preparing to install zone <myzone>
[Output from zoneadm, this may take a few mins]
4. Boot the zone to complete the installation, using the zoneadm command.
Global# zoneadm -z myzone boot
5. Use the zlogin command to connect to the zone console.
Global# zlogin -C myzone
[Connected to zone 'myzone' console]
[Initial zone boot output, service descriptions are loaded etc.]
It may take a short while for the first boot to configure everything, load all the service descriptors,
and so on. You will need to answer the system configuration details. Some suggestions are:
Terminal=(12)X Terminal Emulator (xterms)
Not Networked
No Kerberos
Name service = None
Time Zone = your-time-zone
root passwd = (Your choice – remember it though!)

The zone will reboot after you have provided the configuration information.
6. Before you can proceed to the next stage, the configured zone needs to be shutdown
(configuration changes are only applied when the zone boots).
Global# zlogin myzone init 5
Allocating an Oracle Solaris ZFS File System to a Zone
Now that you have a zpool (mypool) and a zone (myzone) you are ready to allocate a Oracle Solaris
ZFS file system to the zone.
1. To create a Oracle Solaris ZFS file system, use the Oracle Solaris ZFS create command.
Global# Oracle Solaris ZFS create mypool/myzonefs
2. To apply a quota to the file system, use the Oracle Solaris ZFS set quota command.
Global# Oracle Solaris ZFS set quota=5G mypool/myzonefs
The file system and all of its child file systems can be no larger than the designated quota. Note that
both these steps must be performed in the global zone. Also notice that creating the file system in
Oracle Solaris ZFS is much simpler than with a traditional file system/volume manager combination.

To illustrate the isolation/security properties of containers with Oracle Solaris ZFS, this example now
creates a Oracle Solaris ZFS file system that will remain outside the container. There is no need to
apply a quota to this outside file system.
3. To create this other file system, again use the Oracle Solaris ZFS create command.
Global# Oracle Solaris ZFS create mypool/myfs
4. To show the properties of all the pool and the file systems, use the Oracle Solaris ZFS list
command.
Global# Oracle Solaris ZFS list
NAME USED AVAIL REFER MOUNTPOINT
mypool
mypool/myfs
mypool/myzonefs
396G
98.5K
98.5K
197G
197G
5G
99.5K
98.5K
98.5K
/mypool
/mypool/myfs
/mypool/myzonefs
To make the file system (myzonefs) available in the zone (myzone), the zone configuration needs to be
updated.
5. To update the zone configuration, use the zonecfg command.
Global# zonecfg -z myzone
zonecfg:myzone> add dataset
zonecfg:myzone:dataset> set name=mypool/myzonefs
zonecfg:myzone:dataset> end
zonecfg:myzone> commit
zonecfg:myzone> exit
The mypool/myzonefs file system is now added to the zone configuration. Note that these steps must
be performed with the zone shut down, otherwise the zone configuration changes would not be visible
until the next reboot. To check that the zone is shut down try logging into it using zlogin myzone. If
the zone is shut down the login will fail; if the zone is running you will see a login prompt—login as
root and shut the zone down with init 5. These steps are performed in the global zone.
6. Now boot the zone.
Global# zoneadm -z myzone boot
7. Log in to the zone. (Leave a few seconds for the zone to boot.)
Global# zlogin -C myzone
[Connected to zone 'myzone' pts/3]
[Usual Solaris login sequence]
8. List the Oracle Solaris ZFS file systems in the zone
NAME USED AVAIL REFER MOUNTPOINT
mypool
mypool/myzonefs
0M
8K
200B
5G
—
8K
/mypool
/mypool/myzonefs

Creating New File Systems

Administering Oracle Solaris ZFS file systems from the non-global zone is done just like it is in the
global zone, although you are limited to operating within the file system that is allocated to the zone
(mypool/myzonefs). New Oracle Solaris ZFS file systems are always created as a child of this file
system because this is the only Oracle Solaris ZFS file system the non-global zone can see. The
administrator in the non-global zone can create these file systems. There is no need to involve
administrator of the global zone, though the administer could do so if it were necessary.

1. To create a new file system, use the Oracle Solaris ZFS create command.
Global# Oracle Solaris ZFS create mypool/myzonefs/tim
Global# Oracle Solaris ZFS list

The non-global zone administrator can create as many child file systems as s/he wants and each child
file system can have its own file systems, and in that way form a hierarchy.
As a demonstration that the non-global zone administrator is limited to the assigned file systems, this
example demonstrates trying to break security by creating a file system outside the container's "space".
2. Try to create another file system outside of mypool/myzonefs, using the Oracle Solaris ZFS create
command. As you can see, Oracle Solaris ZFS and zones security denies permission for the nonglobal
zone to access resources it has not been allocated and the operation fails.
MyZone# Oracle Solaris ZFS create mypool/myzonefs1
cannot create 'mypool/myzonefs1': permission denied
Applying Quotas to the File Systems
Typically, to prevent the user consuming all of the space, a non-global zone administrator will want to
apply a quota to the new file system. Of course, the child's quota can't be more than 5 GB as that is the
quota specified by the global zone administrator to all of the file systems below mypool/myzonefs.
To set a quota on our new file system, use the Oracle Solaris ZFS set quota command.
MyZone# Oracle Solaris ZFS set quota=1G mypool/myzonefs/tim
MyZone# Oracle Solaris ZFS list
The administrator of the non-global zone has set the quota of the child file system to be 1G. They
have full authority to do this because they are operating on their delegated resources and do not need
to involve the global zone administrator.
The Oracle Solaris ZFS property inheritance mechanism applies across zone boundaries, so the nonglobal
zone administrator can specify his/her own property values should s/he wish to do so. As with
normal Oracle Solaris ZFS property inheritance, these override inherited values.
Changing the Mountpoint of a File System
Now that the file system is set up and has the correct quota assigned to it, it is ready for use. However,
the place where the file system appears (the mountpoint) is partially dictated by what the global zone
administrator initially chose as the pool name (in this example, mypool/myzonefs). But typically, a
non-global zone administrator would want to change it.
To change the mountpoint, use the Oracle Solaris ZFS set mountpoint command.
MyZone# Oracle Solaris ZFS set mountpoint=/export/home/tim mypool/myzonefs/tim
MyZone# Oracle Solaris ZFS list
Note that the mountpoint can be changed for any file system independently.
Setting the Compression Property
The next example demonstrates the compression property. If compression is enabled, Oracle Solaris
ZFS will transparently compress all of the data before it is written to disk. The benefits of compression
are both saved disk space and possible write speed improvements.
1. To see what the current compression setting is, use the Oracle Solaris ZFS get command..
MyZone# Oracle Solaris ZFS get compression mypool mypool/myzonefs
mypool/myzonefs/tim

Be aware that the compression property on the pool is inherited by the file system and child file
system. So if the nonglobal zone administrator sets the compression property for the delegated file
system, it will set it for everything below, as well.
2. To set the compression for the file system, use the Oracle Solaris ZFS set command.
MyZone# Oracle Solaris ZFS set compression=on mypool/myzonefs
3. Examine the compression property again in the non-global zone. Note the compression property
has been inherited by mypool/myzonefs/tim as with normal Oracle Solaris ZFS administration.
MyZone# Oracle Solaris ZFS get compression mypool mypool/myzonefs
mypool/myzonefs/tim

Taking a Snapshot

One of the major advantages of Oracle Solaris ZFS is the ability to create an instant snapshot of any
file system. By delegating a file system to a non-global zone this feature becomes available as an option
for the non-global zone administrator.
To take a snapshot named “1st “ of the file system, use the Oracle Solaris ZFS snapshot command.
MyZone# Oracle Solaris ZFS snapshot mypool/myzonefs@1st
MyZone# Oracle Solaris ZFS list

As with Oracle Solaris ZFS file systems in the global zone, this snapshot is now accessible from the
root of the file system in .Oracle Solaris ZFS/snapshot/1st.

Conclusion

Once a zone has been created and a Oracle Solaris ZFS file system has been allocated to it, the
administrator for that (non-global) zone can create file systems, take snapshots, create clones, and
perform all the other functions of an administrator—within that zone. Yet the global zone, and any
other zones, are fully isolated from whatever happens in that zone.
The integration of Oracle Solaris Containers and Oracle Solaris ZFS is just another way that Oracle
Solaris 10 is providing cost benefits to customers by allowing them to safely consolidate applications
and more easily manage the data those applications use.